This invention is directed generally to a load indicator washer and in particular to a load indicator washer for use with a mine roof bolt.
Load indicator washers for use with mine roof bolts are broadly old as disclosed, for example, in U.S. Pat. Nos. 3,104,645 to Harrison (1963) and 3,150,557 to Brown (1964).
Harrison discloses a bolt stress indicator which indicates excessive stress imparted to a bolt by an extrusion and resulting deflection of cantilevered flags disposed between the mine roof ceiling and the supporting bolt.
Brown discloses a bolt loading indicator having obliquely set flats whose position is changed as a load is applied to a bolt which extends through the indicator.